1. Field of the Invention
This invention relates to a sheet sorter device for sorting sheets discharged from any of various apparatuses.
2. Description of the Prior Art
Where a plurality of sets of multi-paged documents are to be prepared in a copying or printing operation using an electrophotographic or other copying machine or a simple printer or the like, much labor and time is required in the so-called page-up which is the work of arranging the documents in order of page numbers and grouping them into individual sets of documents and moreover, such page-up is often susceptible of mistakes or errors.
When preparing a plurality of sets of multi-paged documents by the copying or printing operation, the relation between the number of the sets Mi (i=1, . . . , m) and the multi-paged original Oj (j=1, . . . , n) and the copies Cij may be represented as by the matrix in Table 1 below.
Table 1 ______________________________________ Mi Oj 1 2 3 . . . n ______________________________________ 1 C.sub.11 C.sub.12 C.sub.13 . . . C.sub.1n 2 C.sub.21 C.sub.22 C.sub.23 . . . C.sub.2n 3 C.sub.31 C.sub.32 C.sub.33 . . . C.sub.3n . . . . . . . . . . . . . . . m C.sub.m1 C.sub.m2 C.sub.m3 . . . C.sub.mn ______________________________________
There are two types of the copying procedure, namely, (1) the procedure which follows the columns in the above matrix and (2) the procedure which follows the rows in the above matrix. The procedure (1) which follows the columns is one which prepares copies by following the pages for each set, and this corresponds to the case that an automatic original feed device is operatively associated with a copying machine or the like. In contrast, the procedure (2) which follows the rows is one which continuously prepares a desired number of sets of one page and then a corresponding number of sets of other pages in succession and this latter procedure is generally popular. In this latter procedure, copies of the same page are piled as one set and it is therefore necessary that the copies be rearranged in order of page numbers and also be grouped and placed on distinct trays so that they may be removed separately from set to set.
To that end, there has been proposed a device which automatically distributes those copies upon copying or printing.
Some large high-speed machines have been provided with a sorter connected to the copy discharge port thereof for automatically paging up copies discharged from the discharge port.
However, such device is large-scaled and expensive and it has only been used in the places where great quantities of documents are handled (such as copy centers or the like). In the copying work carried out in common offices, page-up has been usually accomplished manually.
Also, to enhance the efficiency of the copying work using copying machines, it is necessary to rationalize the work of document rearrangement which occupies a considerable part of the copying work, such as replacement of originals, page-up of the copies produced, etc. For the automatic replacement of originals, there have already been contrived automatic original feed devices. These devices are either of the following two types: (1) the system whereby an automatic sheet original feed device is installed in a slit exposure section for the exposure of sheet originals, wherein the device is provided in addition to the original carriage for thick originals; and (2) the system whereby sheet originals are automatically fed onto the original carriage for thick originals. This latter system (2) may be adapted to be installed on the body of a copying machine with few alterations of the design of the machine. Nevertheless, in the designing of the plate on which the original to be copied is placed under pressure, some special technique is required for transporting sheet originals onto the glass surface and stopping them thereon and this is technically difficult and costly. Further, the copying speed in this system is equal to the copying speed for the ordinary thick originals and its only merit is the ease with which originals are handled. Still further, the plate on which the original to be copied is placed under pressure may often interfere with the copying operation for thick originals.
The former system (1) requires a sheet original exposure slit (optical path for exposure) to be provided in the body of the copying machine, which in turn would often involve some difficulties in the designing of the machine body, but in this system, sheet originals need only pass the exposure slit and this leads to a great ease with which the automatic original feed device of this type may be designed. Accordingly, this system is highly reliable and low in cost. Moreover, as compared with the latter system (2), it is meritorious in that the portion corresponding to the backward stroke of the optical system which effects the slit exposure is eliminated and the time corresponding thereto is saved, so that the copying speed is increased to double the copying speed of the latter system. Further, in this system, the carriage for thick original and the automatic sheet original feed device are completely independent of each other so that copying of sheet originals can cut in when copying of a thick original is taking place. However, the passage of one sheet original through the device results in production of only one copy and therefore, if a plurality of copies are desired, the same original must be repositioned as often as the number of the copies desired.
With the compact copying machines used in common offices, it is rarely the case that multiple sets of copies are required and for this reason, the former system (1) is more preferred.